1. Field
The present invention relates to an optical disk apparatus that plays an optical disk, such as a CD and a DVD, and more particularly, to a portable optical disk apparatus provided with a display and speakers for outdoor use.
2. Description of the Related Art
An optical disk apparatus in the related art that plays back videos and audios recorded in an optical disk, is such as a CD or a DVD, has been put into practical use, and is now in widespread use. A portable (mobile) optical disk apparatus provided with relatively small display and speakers for outdoor use is put into practical use. A typical optical disk apparatus is provided with a selector switch that switches an output to an internal signal or an external signal. The internal signal referred to herein means a video signal and a audio signal according to AV data (video data and audio data) recorded in an optical disk, and the external signal means an externally-input video signal and an externally-input audio signal inputted from the outside.
A typical optical disk apparatus in the related art is provided with a switch to maintain a state mechanically manipulated by the user, for example, a slide switch, as the selector switch. The user confirms which of the internal signal and the external signal is selected by confirming the state of the selector switch. Also, the optical disk apparatus in the related art is configured to detect the state of the selector switch by means of a controller for controlling a video signal switching unit that switches video signals (internal signal or external signal) to be output or an audio signal switching portion that switches audio signals (internal signal or external signal) to be output in response to the detected state. The video signal switching unit and the audio signal switching portion in the typical optical disk apparatus in the related art comprise multiplexers.
Also, when the selector switch is manipulated mechanically and switched to a state where the external signal is selected from a state where the internal signal is selected, the optical disk apparatus in the related art generates and outputs a video signal in which an OSD (On Screen Display) image (for example, a character image of “AUX”) indicating the switching of an output to the external signal on videos of the internal signal for a time period (for example, about 5 sec). After the time period has passed since the selector switch is switched to the state where the external signal is selected from the state where the internal signal is selected, a video signal output from the video signal switch portion is switched to the external signal and an audio signal output from the audio signal switching portion is switched to the external signal from the internal signal. In this manner, the switching from the internal signal to the external signal is delayed by a time period from the actual manipulation of the selector switch. The reason why the apparatus is configured in this manner is as follows. That is, when the internal signal is switched to the external signal almost in real time in response to the actual manipulation of the selector switch, an output of videos and audios stops abruptly unless the external signal has been inputted into the main body. Many users misunderstand this event as a failure of the apparatus. This configuration is to avoid such a misunderstanding of the users. Such a misunderstanding readily occurs, in particular, when the user is unaware of having manipulated the selector switch, for example, in a case where the user erroneously manipulates the selector switch while he is making other manipulations on the apparatus main body. The switching from the internal signal to the external signal is therefore delayed for a time period from the actual manipulation of the selector switch for the user to acknowledge the switching to the external signal by seeing the OSD image during this latency in avoiding such a misunderstanding of the user.
Examples of the conventional optical disk apparatuses are disclosed in JP-A-11-149757, JP-A-2003-228400, and JP-A-2002-271715.
The optical disk apparatus in the related art has the audio signal switching circuit including a multiplexer. When the multiplexer is used, however, an audio signal to be output undergoes deformation, which poses a problem that distortion performance of the audio signal to be output is deteriorated.